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Updated: Sep 16, 2025

Ultrasonography of the Adult Male Urinary Tract for Urinary Functional Testing
Published on: August 14, 2019
A prospective study of bladder volume assessment using ultrasound in prostate cancer radiotherapy: Comparison with
B Bąk1, K Kaczmarek2, D Radoła1
1Department of Electroradiology, University of Medical Sciences, Poznań, Poland; Radiotherapy Department II, Greater Poland Cancer Center, Poznań, Poland.
Introduction:
Prostate cancer radiotherapy requires consistent bladder filling to optimize dose delivery and minimize toxicity. This prospective study evaluated the accuracy of ultrasound (US) in bladder volume assessment compared to Cone Beam Computed Tomography (CBCT).
Methods:
22 prostate cancer patients treated with a total dose of 50 Gy in 2 Gy fractions (25 fractions) between August and December 2019 using volumetric arc therapy (VMAT). Prior to initial CT (iCT) scans and during radiotherapy patients consumed 600-800 ml (3-4 cups) of water. Daily ultrasound measurements were taken to determine the mean bladder volume (USGRT) before Cone Beam Computed Tomography (CBCT) imaging, where the radiation therapist contoured the bladder on CBCT scans, calculating bladder volume with a 2 mm margin.
Results:
A total of 1650 ultrasound measurements were performed. Statistical analysis included the Wilcoxon rank test and Spearman correlation to compare bladder volumes. The mean bladder volume measured by the US was 286 ml (SD ± 118), while CBCT recorded 241 ml (SD ± 124), with a strong correlation (r = 0.888, p < 0.001). The coefficient between USGRT and V2CBCT was r = 0.84 (p < 0.0001), indicating a significant correlation.
Conclusion:
The Echoson® bladder scanner showed potential as a non-invasive alternative for daily bladder volume monitoring, reducing radiation exposure and streamlining treatment workflows. The bladder filling protocol is suitable for all patients, with a clinically acceptable measurement error of 17 %.
Implications For Practice:
Ultrasound enhances daily IGRT verification while minimizing radiation dose from CBCT.
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